1. Field of the Invention
Apparatuses and methods consistent with the present general inventive concept relate to image forming apparatuses to form an image on a print medium by use of a developer, and image forming methods thereof, and more particularly, to an image forming apparatus which is provided with a plurality of developers different in densities and colors, and an image forming method thereof.
2. Description of the Related Art
If data including image information are input, an image forming apparatus forms a visible image on a print medium using a developer such as ink or toner. The image forming apparatus performs a halftoning process to express a difference in brightness included in the image information as an image.
The image forming apparatus forms an image on a print medium in two ways: forming dots using a developer on a print medium and a different type of process that does not form dots using a developer. The halftoning process converts input data into a gray-scale image and then into a binary image with respect to whether to form dots or not. When a user visually receives the final image formed by the halftoning process, the user can recognize it by continuous differences in brightness thereof, by causing a spatial integration as his/her vision and brain react.
The image forming apparatus forms images using developers each having a single density, causing the halftoning process to be segmented and complicated. To solve this problem, a technique to provide a plurality of developers having similar colors but different densities to an image forming apparatus and properly use each developer in accordance with brightness of an image has been suggested. The image forming apparatus divides input data with respect to channels corresponding to respective developers based on different densities, forms an image for each channel using the corresponding developer, and overlaps the formed images, to thereby form a halftone image.
However, any one of the developers having different densities may be used up before others as a result of repeated print operations. The conventional image forming apparatus has difficulty in forming an image using the channel corresponding to the used-up developer, thereby resulting in causing the final image formed on a print medium to be poor in quality.
Taking this into consideration, it is necessary to maintain the image quality or at least keep deterioration of the image at a minimum even when any one of the plurality of developers having different densities is used up.